A method for maintaining an access network based on Ethernet is defined in the Operation Administration and Maintenance (OAM) in the seventh section of the Broadband Forum (BBF) standard TR101. In the section, the following four levels of administration domains are defined based on the method of the IEEE standard 802 lag and in combination with the actual situation of the access network: customer, carrier, intra-carrier and end access link. In each domain, the function of a Maintenance End Point (MEP) is implemented between two end points, and the function of a Maintenance Intermediate Point (MIP) is implemented in the middle of a link. An Ethernet OAM message is sent, forwarded and replied between the MEP and the MIP to help to locate a specific failure interrupt area in the Ethernet.
The four administration domains defined in the standard above are mainly to provide an end-to-end method for a carrier in the Ethernet to help the carrier diagnose and determine a link failure. The original access technology is mainly a Digital Subscriber Line (DSL) technology, therefore, an Access Node (AN) mainly behaves as an independent Digital Subscriber Line Access Multiplexer (DSLAM) device. After the PON technology is introduced into the access network, the original separate access node has been expanded into a network which is formed by an Optical Line Terminal (OLT), an Optical Network Unit (ONU) and an Optical Distribution Network (ODN).
For the end-to-end customer domain, all the terminals of the whole network are subjected to Ethernet OAM configuration, as a result, the operation cost of the network is high, and the whole network cannot be applied commercially easily. Whereas, for the whole network, a failure generally occurs in an access network, therefore, to deploy the Ethernet OAM, the most important is to enable an Ethernet OAM function in the access link maintenance domain.
Specifically, for a PON system, the Ethernet OAM between a User Network Interface (UNI) of the ONU and the uplink port of an access Remote Gateway (RG) or a home gateway is especially important. The Ethernet OAM function is generally enabled by the ONU, thus a high requirement is set for the ONU device, and the ONU device is relatively complex to configure and administrate and prone to be configured wrongly. Moreover, each remote gateway or home gateway is different in equipment configuration, so that the construction cost and the operation cost of the whole PON cannot be controlled effectively.